This application is based on Japanese Patent Application 2000-224245, filed on Jul. 25, 2000, the entire contents of which are incorporated herein by reference.
a) Field of the Invention
The present invention relates to a semiconductor device manufacture method and a semiconductor device, and more particularly to a method of manufacturing semiconductor devices by dividing a wafer into chips and such semiconductor devices.
b) Description of the Related Art
In the manufacture processes of semiconductor integrated circuit devices, a process of grinding (back grind) and polishing the back surface of a semiconductor wafer formed with electronic circuits is performed in some cases. With this process, a semiconductor chip can be thinned to a desired thickness.
During grinding and polishing the back surface of a semiconductor wafer, micro cracks may be formed on the back surface of the semiconductor wafer because of mechanical stresses during grinding and polishing. If the semiconductor wafer is divided into a plurality of chips under this condition, chipping and chip cracks are likely to be formed. Chipping and chip cracks formed in a chip lower the flexural strength of the chip. The flexural strength is lowered considerably particularly when the chip is made thin.
It is an object of the present invention to provide a semiconductor device manufacture method and semiconductor devices, capable of suppressing a flexural strength of a chip from being lowered by chipping and chip cracks.
According to one aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of: preparing a plurality of chips divided from a semiconductor wafer having a plurality of semiconductor integrated circuits formed on a front surface of the wafer, front surfaces of the chips being bonded to a first wafer sheet; covering a back surface and side surfaces of each chip bonded to the first wafer sheet, with a reinforcing thin film; and removing each of the plurality of chips from the first wafer sheet.
According to another aspect of the present invention, there is provided a semiconductor device comprising: a semiconductor chip having an integrated circuit formed on a front surface of the semiconductor chip; and a reinforcing thin film covering a back surface opposite to the front surface, and side surfaces of the semiconductor chip.
Since the back surface and side surfaces of the chip are covered with the reinforcing thin film, the mechanical strength of the chip can be increased. If a semiconductor wafer is thinned by grinding it, the mechanical strength of a chip is lowered by micro cracks or the like. Therefore, the reinforcing thin film is effective particularly when a semiconductor wafer is ground thinner.